PRO BOAT UL-19XR_Bashing a UL-19 into an outrigger...

[sammyha]

The angles for laying the fiberglass over...

[sammyha]

It worked as planned!

The mold is reversed, the angle is cut out, and I've got to lay some more glass...


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[sammyha]

Both sponsons are fiberglassed square in the back section. I have made some progress on the sponson formers and boom tube install.

Here's a sketch of what needs done in there. Some of the criteria I needed to figure out are...

1)Support/ strength
2) Bonding surface of formers
3) Accurate location
4) Access to do the above
5) Bonding surfaces to close up the sponsons

The dark lines in the sketch with arrows pointing to them are the support and bonding surfaces of the formers...


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[sammyha]

So there's some real challenges to figure out for this part of the build.

The rear boom tube install is very conventional, epoxy in a front and rear cross former for support and bonding surfaces, drill the outside for the boom tube and put two doublers against the inside walls for final location and epoxy the boom tube in place.

Here's how I'll get the front boom tube in place accurately and epoxied in. Remember, it's buried inside the sponson...

The sketch above showed two cross formers and one longitudinal former for the front boom tube, making a box, open on one side.

After the box is epoxied in place, I'll make two close fitting doublers to slide in the box, the inner one is the doubler in the sketch below, the second one will close the box and support the boom tube on the tub side of the sponson.

Whew! A bit long winded, but had to be figured out, even before I cut one piece of wood...

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[sammyha]

I cut out paper templates for every former. No two formers were the same. I have the rear of the sponson framed for bonding surfaces to close up the sponsons. The wood blocks are for spacing, they will be removed after the epoxy sets...


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[sammyha]

Here you can see the access opening I cut for epoxying in the front formers. The longitudinal former is not made yet.

I'll notch the cross formers and epoxy a stringer top and bottom for bonding surfaces last, they can't be tilted and put in with the stringers in place like the rear ones could. They still need to be trimmed flush too...


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[sammyha]

I successfully pulled the boat from the jig to check the angles... without committing to epoxying anything in place.

Here's what I did. The front blocks are double side taped to the formers while fitting them. But I need to pull the blocks after I epoxy the formers in. So I drilled and pinned them. Then I'll pull the pins to remove the blocks.


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[sammyha]

The back formers are captured and rides on flat surfaces, so a piece of tape holds the formers in place. The front ones want to slide down the angle...

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[sammyha]

Here it is! We're getting in range now...


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[sammyha]

Checking all the angles with a pitch gauge on the actual surfaces...

I got 3.4 degrees on the outside sponson, and 3.9 degrees on the inside sponson. The rear air relief came in at 1.4 degrees.

I can make final adjustments when I epoxy the doublers in place, outside the jig, again checking actual surfaces...

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[srislash]

Here it is! We're getting in range now...

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Ok I love the whole concept and the work into it will become great knowledge for future builds. But please tell me you will keep the same stock paint scheme? I love the modded look of it.

[sammyha]

Ok I love the whole concept and the work into it will become great knowledge for future builds. But please tell me you will keep the same stock paint scheme? I love the modded look of it.

Absolutely! I had the same thought. I want to retain as much "flavor" of the UL-19 as possible...

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[sammyha]

you should pay attention to the relationship between the CG location and the sponson trailing edge is in your design in comparison to the RSX380.
This will guide you on for / aft placement of your sponsons.

I saw this earlier and forgot about it, sorry. I wanted to ask you, shouldn't you place the sponsons conventionally, and build so the CG comes out where it needs to be?

By conventionally I mean I'm taking measurements from the RSX380, which is convenient since I made mine the same length and I'm not a designer.

Btw, the sponsons measure the same, real close. The step will be in the same location.

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[larryrose11]

I saw this earlier and forgot about it, sorry. I wanted to ask you, shouldn't you place the sponsons conventionally, and build so the CG comes out where it needs to be?

By conventionally I mean I'm taking measurements from the RSX380, which is convenient since I made mine the same length and I'm not a designer.

Btw, the sponsons measure the same, real close. The step will be in the same location.

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The trailing edge of the sponsons (ride pads) and the prop are what support the weight of a rigger.
The distance from the prop to the CG should be about 60-80% of the distance between the prop and the ride pads. Some riggers have shoes, such as your RSX380, which can change this be closer to the 60% mark. Measure your RSX380 sponson ride pads, and CG in reference to prop location. Call the prop location Zero coordinate. you this ratios as a guide for the CG of your UL-19XR and make sure you can move the batteries around a bit so you can move the CG. Another option is to extend the ride surface of the sponsons.

[sammyha]

Sweet. More good info. I didn't think about the CG location changing without rear shoes. Thanks, that will surely help with trimming this rigger.

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[sammyha]

Custom one-off boats take lots of time to produce. That's just how it is. A big part of the time is spent figuring things out.

This is all I got done tonight. I used a stiffer material to make the template for the inner former, with a screw in it to reach in there and fit it.

The double sided tape is removed and I used the pin clamps to hold it together while I epoxied the longitudinal former on.

The former assembly slides in nicely without binding.

Note: The challenge for the front former assembly is matching the steep changing angles in the front of the sponson and holding the position of the assembly while epoxying it in place...

The other side will go faster...

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[sammyha]

Here's a link to a video I made for the guys on YouTube. Gives a bit more insight to this setup thru video...
https://youtu.be/AtJQzzDCJG0

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[sammyha]

Woo Boy! Major progress...

Actually this is just a culmination of all my figuring, setups and fabrication coming together. First I epoxied the formers in, just tacked them in, top and bottom. All of them, front and back.

Then I successfully pulled the pins from the front former assemblies. And removed all the blocks.

Then I pulled the sponsons from the jig and epoxied all the joints...

Note: Edited for clarity



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[sammyha]

Then I drilled the back holes thru the sides of the sponsons by drilling thru the hole in the blocks from the inside.

With the sponsons back in the jig, and the blocks back in place aligning sponson rods, I dremeled out the holes to fit the sponson tubes, eyeballing it to the sponson rods.

Note: Edited for clarity



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[sammyha]

Note: I edited the two posts before this one for clarity

Now I have all the pieces made. I'll just roll some pictures, no explanations needed.

The only thing I'll add is I made two inner doublers for each sponson tube. They both are located in pockets, so I have total support in every direction.

So I can take it out of the jig and check the angles. If I need to adjust any angles, I'll sand the correct side of the inner doubler that needs to be moved. Then simply shim it to hold it in place during final epoxying.

I'm thinking it won't take much, the angles should be very close to right on...

Here's the front sponson tube...


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[sammyha]

And here's the rear sponson tube along with an overall shot of the right sponson...


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[sammyha]

Well, I made two of every component I posted about here yesterday. For the left side...

I'm done with fabricating sponson parts!

I put a video up on YouTube about making the last piece. And some on how this all goes together...

https://youtu.be/8-L3ch-qlDA

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[sammyha]

But...

The really good stuff comes next! Here's a teaser...


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[sammyha]

It's off the jig and I've checked the sponson angles. Amazing results.

Check out this video...

https://youtu.be/GX56ejbht4E

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[sammyha]

I have more...

So I figured if I got that bottom surface qualified level, and the inside of the sponson square, that would be at least as good as it was on the original boat.

Here's a shot of the ride pad of the inside sponson. It should be level...

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[sammyha]

And here's the outside sponson ride pad, which has some angle up so it doesn't grab on the left turns...


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[sammyha]

I've adjusted the AOA, and final epoxied in the sponson tubes and formers.

The right sponson only needed a touch less angle(3.9 to 3.7 degrees) and a slight tilt for the ride pad to be flat. So I sanded one former a bit more than the other...



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[sammyha]

The left sponson was off more(3.6 need 3.2 degrees). I shimmed my pitch gauge with cardboard to get an idea for how much to sand. It needed twice that much due to the moment arm length to the front sponson tube versus the length of my pitch gauge.

I marked the formers, sanded them and did a dry check.

Then epoxied in shims to hold the formers against the side of the box...



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[sammyha]

I have to say this was fairly simple to do. And everything I've been measuring checked out good after final epoxy.

I've locked the formers in with peanut butter too...

For the record, here's a check on my RSX380. The accuracy of laser cut kits...

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[Elekoz]

awesome work! keep it up